Cyclodextrin-grafted TiO2 nanoparticles: synthesis, complexation capacity, and dispersion in polymeric matrices

The modification of the surface of titanium dioxide nanoparticles (TiO2 NPs) by the incorporation of cyclodextrins (CDs), cyclic oligosaccharides with a hydrophobic cavity, can largely improve the functionality of TiO2 by lodging molecules of interest in the CD to act directly on the surface of the nanoparticles or for further release. With this aim, we have synthesized beta CD-modified nanoparticles (beta CDTiO2 NPs) by a two-step reaction that involves the incorporation of a spacer and then the linking of the macrocycle, and characterized them by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The capacity of the functionalized structures to trap model compounds (Rhodamine and 1-naphthol) has been compared to that of bare TiO2 NPs by fluorescence and Ultraviolet-visible (UV-visible) spectroscopy. The presence of the CDs on the surface of the TiO2 avoids the photo-degradation of the guest, which is of interest in order to combine the photocatalytic activity of TiO2, one of its most interesting features for practical purposes, with the delivery of compounds susceptible of being photo-degraded. The beta CDTiO2 NPs have been dispersed in polymeric matrices of frequently used polymers, polyethylene (LDPE) and polyethylene oxide (PEO), by cryogenic high energy ball milling to produce nanocomposites in the form of films. The surface modification of the nanoparticles favors the homogenization of the filler in the matrix, while the nanoparticles, either in bare or functionalized form, do not seem to alter the crystallization properties of the polymer at least up to a 5% (w/w) load of filler

Cyclodextrin-grafted TiO2 nanoparticles: synthesis, complexation capacity, and dispersion in polymeric matrices

The modification of the surface of titanium dioxide nanoparticles (TiO2 NPs) by the incorporation of cyclodextrins (CDs), cyclic oligosaccharides with a hydrophobic cavity, can largely improve the functionality of TiO2 by lodging molecules of interest in the CD to act directly on the surface of the nanoparticles or for further release. With this aim, we have synthesized beta CD-modified nanoparticles (beta CDTiO2 NPs) by a two-step reaction that involves the incorporation of a spacer and then the linking of the macrocycle, and characterized them by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The capacity of the functionalized structures to trap model compounds (Rhodamine and 1-naphthol) has been compared to that of bare TiO2 NPs by fluorescence and Ultraviolet-visible (UV-visible) spectroscopy. The presence of the CDs on the surface of the TiO2 avoids the photo-degradation of the guest, which is of interest in order to combine the photocatalytic activity of TiO2, one of its most interesting features for practical purposes, with the delivery of compounds susceptible of being photo-degraded. The beta CDTiO2 NPs have been dispersed in polymeric matrices of frequently used polymers, polyethylene (LDPE) and polyethylene oxide (PEO), by cryogenic high energy ball milling to produce nanocomposites in the form of films. The surface modification of the nanoparticles favors the homogenization of the filler in the matrix, while the nanoparticles, either in bare or functionalized form, do not seem to alter the crystallization properties of the polymer at least up to a 5% (w/w) load of filler

Impact of sex, age, and risk factors for venous thromboembolism on the initial presentation of first isolated symptomatic acute deep vein thrombosis

BACKGROUND AND AIMS: Sex-specific differences exist for the initial presentation of acute venous thromboembolism (VTE): men are more likely to present with proximal deep vein thrombosis (DVT) in the lower limbs (versus pulmonary embolism [PE] or isolated distal DVT [IDDVT]) than women. We studied in detail the influence of sex, age, and VTE risk factors on the initial presentation of IDDVT versus proximal DVT. METHODS: A total of 24,911 patients with a first episode of objectively diagnosed acute symptomatic lower-limb DVT (without symptomatic PE) were enrolled in RIETE (years 2000-2017) and included in the present analysis. RESULTS: A total of 4266 (17.1%) patients had IDDVT. No trend for more IDDVT diagnoses was observed over time. Women aged 40-69 had a higher proportion of IDDVT, especially between 40 and 49 years (+6.7%; 95CI +3.7%; +9.9%), whereas men had more often proximal DVT. The presenting location of first acute DVT depended on sex, age, and the prevalence and type of VTE risk factors. Recent surgery was independently associated with a diagnosis of IDDVT in both women and men, whereas active cancer and pregnancy were associated with proximal DVT. CONCLUSIONS: The interaction between age and VTE risk factors influences the presenting location (distal versus proximal) of the first acute lower-limb DVT observed in women and men. Our observations extend to IDDVT the concept that different clinical manifestations of acute VTE may not fully share the same pathophysiological mechanisms: this contributes to explain sex-specific prognostic differences.status: publishe